This is a variant of the Baade-Wesselink method. If a supernova is a
black body emitter one can calculate source brightness from
temperature; the distance can then be estimated by comparing
source brightness with the observed flux. In SNeII atmosphere
the flux is diluted due to electron scattering opacity. If this
greyness is calculated source brightness can be inferred.
Schmidt, Kirshner
& Eastman (1992)
developed this approach and obtained the distances to SNeII in
agreement with those from the ladder. The point is that
EPM gives absolute distance without zero point calibrations.
The Hubble constant they obtained is 73 ± 9
(Schmidt et
al. 1994).

A possible source of systematic errors is in the estimation of the temperature
from the
spectrum or colour. The SNeII physics also might not be uniform,
as we see occasional large scatters in a
cross-correlation analysis.